Lesser Scaup Aythya affinis

Identification Tips:

• Length: 12 inches Wingspan: 29 inches
• Small, compact diving duck
• Peaked crown
• Yellow eyes
• Blue bill with small black nail at tip
• Dark wing with dark tipped white secondaries and pale gray primaries
• Immature female similar to adult female, immature male is similar to female in autumn, but acquires alternate plumage during winter

Adult male alternate:

• Alternate plumage worn from fall through early summer
• Glossy purplish head
• Black breast
• Whitish or pale gray flanks, white belly
• Whitish back with fine black vermiculations
• Black tail, upper- and under-tail coverts

Adult male basic:

• Similar to adult female

Adult female:

• Distinct white band around base of bill
• Dark brown body plumage
• Whitish belly

Similar species:

Adult male Ring-necked Duck similar in alternate plumage but has quite different bill pattern, black back, grayer flanks and vertical white finger just behind black breast. Greater Scaup is very similar but has a more rounded head, larger bill, dark-tipped white primaries and secondaries, and glossy, greenish head as an adult male in alternate plumage. Female Greater Scaup has more rounded head, a broader bill, and more white flight feathers, and frequently has a distinct pale spot behind eye on side of head.

Length and wingspan from: Robbins, C.S., Bruun, B., Zim, H.S., (1966). Birds of North America. New York: Western Publishing Company, Inc.

Above information used courtesy of United States Geological Survey.